Virtual functional units for VLIW processors

Abstract

A virtual functional unit design is presented that is employed in a statically scheduled VLIW processor. ''Virtual'' views of the function unit appear to the processor scheduler that exceed the number of physical instantiations of the functional unit. As a result, significant processor performance improvements can be achieved for those types of functional units that are too difficult or too costly to physically duplicate. By providing different virtual views to the different clusters of a VLIW processor, the compiler / scheduler can generate more efficient code for the processor, than a processor without virtual views and the physical unit restricted to a subset of the processor's clusters. The compiler / scheduler guarantees that the restrictions with respect to scheduling of operations for functional units with multiple virtual views is met. NON-clustered processors also benefit from virtual views. By providing multiple virtual views in multiple issue slots of a physical function unit, the compiler / scheduler has more freedom to schedule operations for the functional unit.

Description

technical field [0001] The present invention relates to microcomputer systems, and more particularly to VLIW processors having many initiator slots with bypass networks, and wherein a single physical function process is virtualized for two or more issue slots with bypass networks device unit. Background technique [0002] Processor design has advanced significantly over the past 50 years. Increasing semiconductor circuit density in general allows higher performance levels to be achieved using fewer components and at reduced cost. When implemented using CMOS process technology, low power implementations become possible. [0003] The embedded consumer market for audio and video processing is cost driven. Such devices were initially implemented using dedicated hardware that could provide the required performance at a lower price than was possible with programmable processors. Subsequently, the increased complexity of newer audio and video standards made programmability more...

AI Technical Summary

Problems solved by technology

[0018] Each LS unit is complex and expensive, so duplicating a second LS unit for the cluster is prohibitively expensive

A multi-ported LS unit that can sustain two load or store operations per VLIW instruction is complex, and an LS unit typically requires a significant amount of chip real estate, and the extra area needed may not be available at all

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